U.S. patent application number 11/373285 was filed with the patent office on 2006-07-13 for electro-optical device and electronic apparatus.
This patent application is currently assigned to Seiko Epson Corporation. Invention is credited to Masao Murade.
Application Number | 20060152665 11/373285 |
Document ID | / |
Family ID | 26623723 |
Filed Date | 2006-07-13 |
United States Patent
Application |
20060152665 |
Kind Code |
A1 |
Murade; Masao |
July 13, 2006 |
Electro-optical device and electronic apparatus
Abstract
An electro-optical device includes a display electrode disposed
in an image display region of a TFT array substrate, a pattern
portion including at least one of wiring and a circuit element
connected to the display electrode directly or through a pixel
switching element and provided in a frame region, which defines the
periphery of the image display region, and a lower shielding film
for covering the TFT array substrate side of at least a portion of
the pattern portion. Therefore, in the electro-optical device such
as a liquid crystal device, a light-dark pattern due to the wiring
and the circuit element provided in the frame region can be
prevented from being projected near the edge of a display
image.
Inventors: |
Murade; Masao; (Suwa-shi,
JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 19928
ALEXANDRIA
VA
22320
US
|
Assignee: |
Seiko Epson Corporation
Tokyo
JP
|
Family ID: |
26623723 |
Appl. No.: |
11/373285 |
Filed: |
March 13, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10259390 |
Sep 30, 2002 |
|
|
|
11373285 |
Mar 13, 2006 |
|
|
|
Current U.S.
Class: |
349/151 |
Current CPC
Class: |
G02F 1/133512 20130101;
G02F 1/13606 20210101; G02F 1/136209 20130101; G02F 1/133388
20210101; G02F 1/13454 20130101; G02F 1/13624 20130101 |
Class at
Publication: |
349/151 |
International
Class: |
G02F 1/1345 20060101
G02F001/1345 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 4, 2001 |
JP |
2001-309103 |
Sep 10, 2002 |
JP |
2002-264521 |
Claims
1. An electro-optical device, comprising: a light exit substrate; a
counter substrate opposing the light exit substrate; a frame-shaped
light shielding layer disposed over the counter substrate and
defining an image display region; a display electrode disposed over
the light exit substrate within the image display region; a pattern
portion disposed over the light exit substrate at a position
overlapping with the frame-shaped light shielding layer and within
the image display region in plan view, the pattern portion being
coupled to the display electrode and including a wiring and a
transistor, the transistor having a drain and a source; a lower
light shielding layer outside the image display region and in
overlap with the frame-shaped light shielding layer in plan view,
the lower light shielding layer covering the pattern portion from a
light exit side of the light exit substrate, the lower light
shielding layer including a drain section confronting the drain of
the transistor and a source section confronting the source of the
transistor, the drain section and the source section of the lower
light shielding layer being separated by a slit.
2. An electro-optical device according to claim 1, wherein the
lower light shielding layer is formed over a flat surface of the
light exit substrate either directly or via a flat underlying
insulating film.
3. An electro-optical device according to claim 1, further
comprising: a pixel switching transistor for switching on and off
application of voltage to the display electrode; and another lower
light shielding layer disposed below at least the channel region of
the pixel switching transistor, the lower light shielding layer and
the other lower light shielding layer being formed from the same
layer.
4. An electro-optical device according to claim 1, wherein the
lower light shielding layer is formed from a light-absorbing
material.
5. An electro-optical device according to claim 4, wherein the
light-absorbing material is at least one of polysilicon and a metal
film with a high melting point.
6. An electro-optical device according to claim 1, wherein the
lower light shielding layer is formed from an electrically
conductive material.
7. An electro-optical device according to claim 1, wherein the
lower light shielding layer is applied at least locally with a
fixed potential.
8. An electro-optical device, comprising: a light exit substrate; a
counter substrate opposing the light exit substrate; a frame-shaped
light shielding layer disposed over the counter substrate and
defining an image display region; display electrode disposed over
the light exit substrate within the image display region; a pattern
portion disposed over the light exit substrate at a position
overlapping with the frame-shaped light shielding layer and within
the image display region in plan view, the pattern portion being
coupled to the display electrode and including a wiring and a
transistor; a lower light shielding layer outside the image display
region and in overlap with the frame-shaped light shielding layer
in plan view, the lower light shielding layer covering the pattern
portion from a light exit side of the light exit substrate, the
lower light shielding layer including a drain section confronting
the drain of the transistor and a source section confronting the
source of the transistor, the drain section and the source section
of the lower light shielding layer being island shaped so that the
drain section and the source section are isolated from each
other.
9. An electro-optical device according to claim 8, wherein the
lower light shielding layer is formed over a flat surface of the
light exit substrate either directly or via a flat underlying
insulating film.
10. An electro-optical device according to claim 8, further
comprising: a pixel switching transistor for switching on and off
application of voltage to the display electrode; and another lower
light shielding layer disposed below at least the channel region of
the pixel switching transistor, the lower light shielding layer and
the other lower light shielding layer being formed from the same
layer.
11. An electro-optical device according to claim 8, wherein the
lower light shielding layer is formed from a light-absorbing
material.
12. An electro-optical device according to claim 11, wherein the
light-absorbing material is at least one of polysilicon and a metal
film with a high melting point.
13. An electro-optical device according to claim 8, wherein the
lower light shielding layer is formed from an electrically
conductive material.
14. An electro-optical device according to claim 8, wherein the
lower light shielding layer is applied at least locally with a
fixed potential.
15. An electro-optical device, comprising: a light exit substrate;
a counter substrate opposing the light exit substrate; a
frame-shaped light shielding layer disposed over the counter
substrate and defining an image display region; display electrode
disposed over the light exit substrate within the image display
region; a pattern portion disposed over the light exit substrate at
a position overlapping with the frame-shaped light shielding layer
and within the image display region in plan view, the pattern
portion being coupled to the display electrode and including a
wiring and a transistor; a lower light shielding layer outside the
image display region and in overlap with the frame-shaped light
shielding layer in plan view, the lower light shielding layer
covering the pattern portion from a light exit side of the light
exit substrate, the lower light shielding layer having an
island-shaped portion that overlaps the transistor of the pattern
portion.
16. An electro-optical device according to claim 15, wherein the
island-shaped portion of the lower light shielding layer that
overlaps the transistor is in an electrically floating
condition.
17. An electro-optical device according to claim 15, wherein the
island-shaped portion of the lower light shielding layer that
overlaps the transistor has the same electric potential as the gate
potential of the transistor.
18. An electro-optical device according to claim 15, wherein the
lower light shielding layer is formed over a flat surface of the
light exit substrate either directly or via a flat underlying
insulating film.
19. An electro-optical device according to claim 15, further
comprising: a pixel switching transistor for switching on and off
application of voltage to the display electrode; and another lower
light shielding layer disposed below at least the channel region of
the pixel switching transistor, the lower light shielding layer and
the other lower light shielding layer being formed from the same
layer.
20. An electro-optical device according to claim 15, wherein the
lower light shielding layer is formed from a light-absorbing
material.
21. An electro-optical device according to claim 20, wherein the
light-absorbing material is at least one of polysilicon and a metal
film with a high melting point.
22. An electro-optical device according to claim 15, wherein the
lower light shielding layer is formed from an electrically
conductive material.
23. An electro-optical device according to claim 15, wherein the
lower light shielding layer is applied at least locally with a
fixed potential.
Description
[0001] This is a Divisional of application Ser. No. 10/259,390
filed Sep. 30, 2002. The entire disclosure of the prior application
is hereby incorporated by reference herein in its entirety.
BACKGROUND
[0002] The present invention relates to the technical field of an
electro-optical device such as a liquid crystal device or the like,
and particularly to the technical field of an electro-optical
device comprising a frame shielding film which defines an image
display region, and an electronic apparatus comprising the
electro-optical device.
[0003] This type of electro-optical device comprises an element
array substrate on which display electrodes such as pixel
electrodes or stripe electrodes, various wirings such as data lines
and scanning lines, switching elements such as pixel-switching thin
film transistors (referred to as "TFT" hereinafter) or thin film
diodes (referred to as "TFD" hereinafter) are formed, and a counter
substrate on which a counter electrode formed in stripes or formed
over the entire surface, and a light shielding film are formed. The
two substrates are disposed opposite to each other. Furthermore, an
electro-optical material such as a liquid crystal is sealed between
the two substrates with a sealing material, and an image display
region in which the display electrodes are arranged is located
nearer to the center (i.e., a region of each substrate which faces
the liquid crystal) than a seal region in which the sealing
material is present. Particularly, in a plan view of the device (as
viewed from the direction perpendicular to the image display
region), the frame region of the image display region is defined as
a frame shape along the inner line of the seal region by the same
film as the shielding film provided on the counter substrate as
described above.
[0004] A built-in peripheral circuit-type electro-optical device is
also generalized, in which peripheral circuits such as a scanning
line driving circuit, a data line driving circuit, a sampling
circuit, an inspection circuit, etc. are formed in the frame region
and the peripheral region in the periphery of the frame region of
the element array substrate.
[0005] Therefore, wirings led from the image display region to the
peripheral region are present in the frame region. Furthermore,
when some of the peripheral circuits such as the sampling circuit,
and the like, which are connected to the wirings, are formed in the
frame region, the circuit elements constituting some of the
peripheral circuits are present in the frame region. Namely, a
pattern comprising the wirings and the circuit elements is present
in the frame region.
[0006] The electro-optical device having the above construction is
contained in a light-shielding mounting case comprising a display
window provided corresponding to the image display region so that
the edge of the display window is positioned near the center line
of the frame region.
SUMMARY
[0007] However, in the above-described electro-optical device, the
pattern comprising the wirings and the circuit elements which are
present in the frame region of the element array substrate, is
formed by patterning a conductive film such as an Al film or the
like. Therefore, in application to a projector in which incident
light has high strength and contains a large quality of oblique
components, the incident light is reflected by the surface of the
pattern portion or passes through spaces of the pattern portion
according to the reflectance. The light reflected by the pattern
portion is reflected by a frame shielding film of chromium (Cr)
provided on the counter substrate. Furthermore, the internally
reflected light reflected by the frame shielding film and the light
passing through the pattern portion are reflected by the back of
the element array substrate to produce reflected light (i), and the
internally reflected light reflected by the frame shielding film
and the light passing through the pattern portion are reflected by
optical elements provided on the emission side of the
electro-optical device, such as a polarizing plate, a retardation
plate, dustproof glass, etc., to produce reflected light (ii). In a
multi-substrate projector comprising a light valve comprising a
plurality of electro-optical devices, light emitted from another
electro-optical device passes through a synthetic optical system
and is reflected by the pattern portion and the frame shielding
film to produce internally reflected light (iii). These lights (i),
(ii), and (ii) are finally mixed with emitted light to emit light
from the electro-optical device.
[0008] Consequently, there is a problem in which a light-dark
pattern (for example, light-dark fringe patterns when a plurality
of wirings are arrayed) is projected near the edge of a display
image corresponding to reflection from or transmission through the
pattern portion. In addition, the surface of the pattern portion
comprising the wirings and the circuit elements has unevenness
corresponding to the unevenness of an under surface and the shape
of the pattern itself. Therefore, internally reflected light
reflected by the uneven surface produces a light-dark pattern by
interference of light, and thus the light-dark pattern finally
mixed in emitted light becomes further remarked according to the
structure of the pattern portion.
[0009] In order to conceal the light-dark pattern projected by
internal reflection from the wirings, a wide frame shielding film
must be formed so as to define the frame region to be significantly
wider than the region on the substrate on which the pattern portion
to be concealed is present. Therefore, it is difficult to comply
with the basic requirement for the electro-optical device to ensure
as a wide image display region as possible on the limited region of
the substrate. Furthermore, in consideration of the fact that the
return light and the internally reflected light are reflected by
the surface of the frame shielding film, which faces the element
array substrate, and finally mixed as light having a light-dark
pattern with emitted light, it is theoretically difficult to
completely conceal the light-dark pattern by simply widening the
frame shielding film.
[0010] The present invention has been achieved for solving the
above-described problem, and an object of the present invention is
to provide an electro-optical device capable of preventing a
light-dark pattern due to a pattern portion comprising wirings and
circuit elements provided on a frame region from being projected
outside a display image, and various electronic apparatus each
comprising the electro-optical device.
[0011] In order to achieve the object, in a first aspect of the
present invention, an electro-optical device comprises display
electrodes arranged in an image display region of a substrate, a
pattern portion comprising at least either of wiring and circuit
elements connected to the display electrodes directly or through
pixel switching elements and provided in a frame region, which
defines the periphery of the image display region, and a lower
shielding film for covering the substrate side of at least a
portion of the pattern portion.
[0012] In the electro-optical device in the first aspect of the
present invention, for example, wirings such as data lines and
scanning lines are led from the image display region and arranged
in the frame region. Besides the wirings or in addition to the
wirings, transistors or circuit elements such as TFTs or TFDs,
which constitute at least some of peripheral circuits connected to
the lead wirings, are arranged in the frame region. Therefore,
image signals are supplied to the display electrodes such as pixel
electrodes through the wirings and the circuit elements provided in
the frame region, directly or through the pixel switching elements
such as TFTs, to permit active matrix driving or passive matrix
driving.
[0013] Particularly, in application to a projector in which
incident light has high strength and contains a large amount of
oblique components, the incident light is reflected by the surface
of the pattern portion, which is formed by patterning a conductive
film, for example, comprising an Al film, or passes through spaces
of the pattern portion according to the reflectance of the pattern
potion. However, in the present invention, in a portion of the
frame region, the substrate side of at least a portion of the
pattern portion comprising the wirings and the circuit elements is
covered with the lower shielding film. Therefore, of the incident
light reflected by the pattern portion or passing through the
spaces of the pattern portion, the quantity of light mixed with
final emitted light for display directly or after internal
refection is decreased by a quantity corresponding to the quantity
of light absorbed or reflected by the lower shielding film. More
specifically, in a multi-substrate projector, for internally
reflected light resulting from further reflection of return light
by the pattern portion and the frame shielding film, the quantity
of the internally reflected light mixed with final emitted light
for display is decreased by a quantity corresponding to the
quantity of light absorbed or reflected by the lower shielding
film.
[0014] Particularly, the surface of the pattern portion comprising
the wirings and the circuit elements has unevenness corresponding
to the unevenness of the lower surface or the shape of the pattern
itself, and thus internally reflected light reflected by the uneven
surface has a light-dark pattern due to interference of light.
However, the light-dark pattern can be decreased by absorption or
reflection by the lower shielding film.
[0015] As described above, in the electro-optical device of the
present invention, the light-dark pattern projected outside the
display image due to the pattern portion comprising the wirings and
the circuit elements provided in the frame region can be decreased.
Therefore, the frame shielding film need not be widened for
concealing the light-dark pattern projected near the edge of the
display image, thereby securing the wide image display region in
the limited region on the substrate.
[0016] In addition, in the electro-optical device of the present
invention, the lower shielding film is provided on a portion facing
the pattern portion, not provided over the entire frame region, and
thus the occurrence of stress can be decreased as compared with a
case in which the lower shielding film is formed over the entire
frame region.
[0017] In the electro-optical device in the first aspect of the
present invention, the frame shielding film is provided above the
pattern portion in the frame region.
[0018] In this case, for example, the frame shielding film
comprises a built-in shielding film formed on the substrate, or a
shielding film formed on the counter substrate opposing the
substrate through the electro-optical material such as the liquid
crystal, and the frame region can be defined by the frame shielding
film provided above the pattern portion. Particularly, the
light-dark pattern projected outside the display image by
internally reflected light reflected by the inner plane of the
frame shielding film according to the pattern portion can be
decreased by the lower shielding film disposed below the pattern
portion.
[0019] In the electro-optical device in the first aspect of the
present invention, the lower shielding film is provided on the flat
surface of the substrate directly or through a flat underlying
insulating film.
[0020] In this case, the lower shielding film is formed provided on
the flat surface of the substrate directly or through the flat
underlying insulating film, and thus the surface of the lower
shielding film has substantially no unevenness. Therefore, even if
return light from the back side of the substrate and internally
reflected light are partially reflected by the lower shielding
film, and mixed with final emitted light for display, the
light-dark pattern due to interference can be decreased because
light reflected by the flat lower shielding film has less
interference.
[0021] In the electro-optical device in the first aspect of the
present invention, the circuit elements include first transistors,
and each of the display electrodes comprises a pixel electrode. The
electro-optical device further comprises second transistors
connected as the pixel switching elements to the pixel electrodes,
the wirings being connected to the second transistors.
[0022] In this case, image signals are supplied to the second
transistors through at least some of the peripheral circuits, for
example, such as a sampling circuit, a scanning line driving
circuit, a data line driving circuit, an inspection circuit, a
pre-charge circuit, etc., all of which are arranged in the frame
region and comprise the first transistors. Switching of the pixel
electrodes is controlled by the second transistors to permit active
matrix driving.
[0023] In the electro-optical device in the first aspect of the
present invention, the same film as the lower shielding film is
provided below the channel region of each of the second
transistors.
[0024] In this case, the lower side of the channel region of each
of the second transistors serving as the pixel switching elements
respectively connected to the pixel electrodes is covered with the
lower shielding film, and it is thus effectively prevent the
phenomenon that return light is incident on the channel regions to
produce a light leakage current, preventing a change in the
characteristics of the second transistors. Incident light incident
on the channel regions of the second transistors from above may be
cut off by the built-in film formed on the substrate, the wirings
comprising an Al shielding film or the like, and the shielding film
provided on the counter substrate, without any problem.
Particularly, the lower shielding film for shielding the second
transistors in the pixel region and the lower shielding film for
preventing the occurrence of the light-dark pattern in the frame
region comprise the same film, and can thus be formed by the same
production step, thereby simplifying the laminated structure on the
substrate and the manufacturing process.
[0025] In the electro-optical device in the first aspect of the
present invention, the lower shielding film comprises a
light-absorbing film.
[0026] In this case, when return light is incident on the surface
of the substrate-side surface of the lower shielding film,
reflected light is decreased by absorption by the lower shielding
film. Therefore, even when the reflected light is finally mixed
with emitted light for display, the light-dark pattern based on the
reflected light can be decreased.
[0027] In this case, the light-absorbing film may contain at least
one of a polysilicon film and a high-melting-point metal film.
[0028] In this construction, the light-absorbing film having an
excellent light-absorbing function can relatively easily be
formed.
[0029] In the electro-optical device in the first aspect of the
present invention, the lower shielding film is formed in an
island-like shape.
[0030] In this case, the lower shielding film is formed in
separated islands, and thus the occurrence of stress due to the
presence of the lower shielding film can be reduced to improve
manufacture yield and reliability of the device, as compared with a
case in which the lower shielding film is formed over the entire
frame region.
[0031] In the electro-optical device in the first aspect of the
present invention, the lower shielding film may comprise a
conductive film.
[0032] In this case, the lower shielding film comprises the
conductive film, and can thus be used not only as the shielding
film but also as the wiring or the like.
[0033] When the lower shielding film comprises the conductive film,
a fixed potential may be supplied to at least a portion of the
lower shielding film.
[0034] In this construction, it is possible to prevent a variation
in the potential of the lower shielding film from adversely
affecting the wirings and the circuit elements in the frame
region.
[0035] Alternatively, when the lower shielding film comprises the
conductive film, at least portions of the lower shielding film,
which are deposited below the first transistors, have a floating
potential.
[0036] In this construction, the portions of the lower shielding
film, which are deposited below the first transistors, have a
floating potential, and it is thus possible to effectively prevent
a variation in the potential of the lower shielding film from
adversely affecting the characteristics of the first
transistors.
[0037] In this case, the portions of the lower shielding film,
which are deposited below the first transistors, may be formed to
include island-like portions which separate the portions of the
lower shielding film, which face the source electrodes of the first
transistors, from the portions of the lower shielding film, which
face the drain electrodes of the first transistors.
[0038] In this construction, the island-like portions of the lower
shielding film separate the portions of the lower shielding film,
which face the source electrodes of the first transistors, from the
portions of the lower shielding film, which face the drain
electrodes of the first transistors, thereby decreasing capacitance
coupling between the source electrodes and the drain electrodes due
to the parasitic capacitance between the lower shielding film and
the source electrodes, and the parasitic capacitance between the
lower shielding film and the drain electrodes. Therefore, high
transistor characteristics can be obtained from the first
transistors.
[0039] When the lower shielding film comprises the conductive film,
at least the portions of the lower shielding film, which are
deposited below the first transistors, may be formed to have slits
which separate the portions of the lower shielding film, which face
the source electrodes of the first transistors, from the portions
of the lower shielding film, which face the drain electrodes of the
first transistors.
[0040] In this construction, the slits of the lower shielding film
separate the portions of the lower shielding film, which face the
source electrodes of the first transistors, from the portions of
the lower shielding film, which face the drain electrodes of the
first transistors, thereby decreasing capacitance coupling between
the source electrodes and the drain electrodes due to the parasitic
capacitance between the lower shielding film and the source
electrodes, and the parasitic capacitance between the lower
shielding film and the drain electrodes. Therefore, high transistor
characteristics can be obtained from the first transistors.
[0041] When the lower shielding film comprises the conductive film,
the lower shielding film may be formed so as not to be deposited
below the channel regions of the first transistors.
[0042] In this construction, the lower shielding film is not
disposed below the channel regions of the first transistors, and it
is thus possible to effectively prevent a variation in the
potential of the lower shielding film from adversely affecting the
characteristics of the first transistors.
[0043] When the lower shielding film comprises the conductive film,
at least the portions of the lower shielding film, which are
deposited below the channel regions of the first transistors, may
have the gate potential of the first transistors.
[0044] In this construction, the portions of the lower shielding
film, which are deposited below the channel regions of the first
transistors, have the gate potential of the first transistors, and
the gate electrodes of the first transistors can be formed above
the lower shielding film to form back channels by those portions of
the lower shielding film. Therefore, the characteristics of the
first transistors can be improved.
[0045] In the electro-optical device in the first aspect of the
present invention, the lower shielding film is formed to extend
from the outer edge of the image display region to the peripheral
side by a predetermined width which is previously set according to
the incidence angle of incident light applied to the frame
region.
[0046] In this case, for example, in application to a projector for
extended projection, the incidence angle of incident light applied
to the frame region is increased, and the lower shielding film is
formed to extend from the outer edge of the image display region to
the peripheral side by the predetermined width previously set
according to the incidence angle. Namely, in the frame region, the
lower shielding film can be formed only in a region necessary for
preventing the light-dark pattern according to the incidence
angle.
[0047] However, in some cases, the effect of the present invention,
i.e., the effect of preventing projection of any image, which
should not be basically displayed, outside the display image,
cannot be sufficiently achieved only by the lower shielding film
covering the pattern portion as described above. Namely, in the
region outside the pattern formation region, i.e., in the region in
which the wirings and the circuit elements are not formed, there is
no light shield, thereby allowing incident light to pass through
that region. The passing light reaches the region outside the
display image to project a dim light image around the display
image, thereby possibly deteriorating the appearance of the
image.
[0048] Therefore, in order to achieve the object, in a second
aspect of the present invention, an electro-optical device
comprises display electrodes arranged in an image display region of
a substrate, a pattern portion comprising at least either of wiring
and circuit elements connected to the display electrodes directly
or through pixel switching elements and provided in a frame region
which defined the periphery of the image display region, a first
lower shielding film for covering the substrate side of at least a
portion of the pattern portion, and a second lower shielding film
comprising the same film as the first lower shielding film and
formed in the frame region except in the region where the pattern
portion is formed.
[0049] In the electro-optical device in the second aspect of the
present invention, for example, wirings such as data lines and
scanning lines are led from the image display region and arranged
in the frame region. Besides the wirings or in addition to the
wirings, transistors or circuit elements such as TFTs or TFDs,
which constitute at least some of peripheral circuits connected to
the led wirings, are arranged in the frame region. Therefore, image
signals are supplied to the display electrodes such as pixel
electrodes through the wirings and the circuit elements provided in
the frame region, directly or through the pixel switching elements
such as TFTs, to permit active matrix driving or passive matrix
driving.
[0050] Particularly, in application to a projector in which
incident light has high strength and contains a large amount of
oblique components, as described above, the incident light is
reflected by the pattern portion or passes through spaces of the
pattern portion, and is then projected on an image, deteriorating
the appearances of the image. Furthermore, in the region other than
the pattern formation region, i.e., in the region in which the
wirings and the circuit elements are not formed, there is no light
shield, thereby allowing incident light to pass through that
region.
[0051] However, in the present invention, the probability that
light is reflected by the pattern portion or passing through the
spaces of the pattern portion, and mixed with light for forming an
image can be decreased by absorption or reflection by the lower
shielding film. This is the same as described above with respect to
the electro-optical device in the first aspect of the present
invention. Particularly, in the present invention, the second lower
shielding film is formed in the region in except the region where
the pattern portion is formed, the passing light can be cut off,
that is, the light can be absorbed or reflected by the second lower
shielding film. Therefore, in the present invention, it is possible
to prevent the phenomenon that a dim light image appears around the
display image, thereby displaying a high quality image with a good
appearance.
[0052] In addition, the first lower shielding film and the second
lower shielding film comprise the same film, thereby simplifying
the manufacturing process or decreasing the manufacturing cost.
[0053] In order to achieve the object, in a third aspect of the
present invention, an electro-optical device comprises display
electrodes arranged in an image display region of a substrate, a
pattern portion comprising at least either of wiring and circuit
elements connected to the display electrodes directly or through
pixel switching elements and provided in a frame region which
defined the periphery of the image display region, a lower
shielding film for covering the substrate side of at least a
portion of the pattern portion, an in-region shielding film
comprising the same film as the lower shielding film and formed to
cover the substrate sides of the channel regions of second
transistors serving as the pixel switching elements, and an
out-of-region shielding film comprising the same film as the lower
shielding film and the in-region shielding film and formed in at
least a portion of a peripheral region around the image display
region, the peripheral region including the frame region.
[0054] In the electro-optical device in the third aspect of the
present invention, for example, wirings such as data lines and
scanning lines are led from the image display region and arranged
in the frame region. Besides the wirings or in addition to the
wirings, transistors or circuit elements such as TFTs or TFDs,
which constitute at least some of peripheral circuits connected to
the led wirings, are arranged in the frame region. Therefore, image
signals are supplied to the display electrodes such as pixel
electrodes through the wirings and the circuit elements provided in
the frame region, directly or through the pixel switching elements
such as TFTs, to permit active matrix driving or passive matrix
driving.
[0055] Particularly, in the present invention, the three types of
the shielding films, i.e., the lower shielding film, the in-region
shielding film, and the out-of-region shielding film, are formed by
using the same film. Of these shielding films, the lower shielding
film avoids the light reflected by the pattern portion or passing
through the spaces of the pattern portion from being mixed with the
image, as described above with respect to the electro-optical
device in the first aspect of the present invention. This can
decrease the light-dark pattern projected near the edge of the
display image.
[0056] On the other hand, the in-region shielding film increases
the light resistance of the second transistors as the pixel
switching elements formed in the image display region. Namely, the
in-region shielding film is formed to cover the substrate sides of
at least the channel regions of the second transistors, and thus
prevents incidence of light on the channel regions and suppresses
the occurrence of a light leakage current from the channel regions.
It is thus possible to prevent the occurrence of a change in the
characteristics of the second transistors, or flickering of an
image due to operation error or the like. Therefore, the quality of
the display image can be improved.
[0057] Furthermore, in the present invention, the out-of-region
shielding film is formed in the peripheral region around the image
display region. The out-of-region shielding film is an idea
including the lower shielding film, and is different from the lower
shielding film in that the formation region of the out-of-region
shielding film is not limited to the frame region. The
out-of-region shielding film can cut off the travel of light
passing through the periphery (i.e., the peripheral region) of the
image display region. Therefore, in the present invention, it is
possible to more effectively prevent the phenomenon that a dim
light image occurs around the display image, thereby permitting the
display of a high-quality image with a good appearance.
[0058] Furthermore, in the present invention, all the lower
shielding film, the in-region shielding film, and the out-of-region
shielding film are formed by using the same film, i.e.,
simultaneously formed in the manufacturing process, thereby
simplifying the manufacturing process or decreasing the
manufacturing cost, as compared with a case in which these films
are separately formed.
[0059] In the electro-optical device in the third aspect of the
present invention, the out-of-region shielding film includes the
second lower shielding film comprising the first lower shielding
film and formed in the frame region except in the region in which
the pattern portion is formed.
[0060] In this case, the second lower shielding film formed in the
frame region except in the region in which the pattern portion is
formed can prevent the passage of light which cannot be
sufficiently prevented only by the first lower shielding film.
Namely, in the region in which the pattern portion comprising the
wirings and the circuit elements is not formed, unconditional
passage of incident light can be prevented. Therefore, in the
present invention, it is possible to more effectively prevent the
phenomenon that a dim light image appears around the display image,
thereby displaying a high quality image with a good appearance.
[0061] In the electro-optical device in the third aspect of the
present invention, peripheral circuits for driving the display
electrodes are provided in the peripheral region so as to be
connected to the pattern portion, and the out-of-region shielding
film is formed in a region other than the region in which a second
pattern portion is formed for connecting at least a pair of
wirings, a pair of circuit elements constituting the peripheral
circuits, and a pair of wiring and circuit element.
[0062] In this case, the out-of-region shielding film is formed in
the region except in the region in which the second pattern portion
is formed for connecting at least a pair of wirings, a pair of
circuit elements constituting the peripheral circuits, and a pair
of wiring and circuit element. Namely, in this case, the
out-of-region shielding film includes a portion formed to "fill" a
portion of the peripheral region, where no element is basically
formed. Therefore, the out-of-region shielding film can further
decease the occurrence of passage of the "passing" light.
[0063] In the portion where the wirings and the circuit elements
constituting the peripheral circuits are formed, "direct" passage
of light is prevented by the wirings and the circuit elements
(i.e., the passage of light is cut off by the wirings and the
circuit elements to some extent). Therefore, the out-of-region
shielding film can be formed in an appropriate and necessary
portion. It is thus possible to realize a relative decease in the
area of the shielding film, and a decrease in the action of
internal stress of the out-of-region shielding film.
[0064] According to circumstance, the out-of-region shielding film
may be formed in the region where the second pattern is formed. In
this case, the out-of-region shielding film is formed over the
entire region to cause the defect that the problem of internal
stress becomes remarked. However, as described above with respect
to the pattern portion, light is also absorbed or reflected by the
second pattern portion, exhibiting a reasonable meaning. Namely,
from the viewpoint of the prevention of mixing of light absorbed or
reflected by the second pattern portion with light for forming the
image, it is meaningful to form the out-of-region shielding film in
the region where the second pattern portion is formed. In this
case, it is proper to briefly express that "the out-of-region
shielding film is formed to cover the entire peripheral
region."
[0065] In the electro-optical device in the second or third aspect
of the present invention, the out-of-region shielding film is
formed in islands.
[0066] In this case, the out-of-region shielding film is formed in
islands, and thus the internal stress of the film can be apparently
decreased, as compared with the shielding film formed over the
entire region. Therefore, it is possible to prevent a trouble in
which the out-of-region shielding film is broken by its own
internal stress, or a trouble in which the internal stress acts on
other elements (for example, an interlayer insulating film) present
around the out-of-region shielding film to cause cracks.
[0067] Particularly, in this case, the distance between the
adjacent islands is 4 .mu.m or less.
[0068] In this construction, the distance between the islands of
the out-of-region shielding film is appropriately set. The reason
for this is described in detail below. When the shielding film is
formed in islands, light possibly passes through the spaces between
the islands. For example, return light incident on the back of the
substrate possibly passes through the spaces. In this case, the
passing light is reflected by the frame shielding film or the like
provided at the back and again passes through the spaces to be
possibly mixed with light for forming the image. However, in the
present invention, the distance between the islands is 4 .mu.m or
less, and thus the above-described possibility less occurs. Namely,
because of the relatively narrow spaces of 4 .mu.m or less, there
is substantially no probability that light passing through the
spaces is reflected by the element provided at the back and again
passes through the spaces. Also, incident light, which is not
return light, possibly passes through the spaces directly. However,
in this case, the influence on the image can be minimized because
of the relatively small distance.
[0069] Therefore, in the present invention, the function of the
shielding films, i.e., the function to prevent the occurrence of a
light image around the display image, can be sufficiently exhibited
while obtaining the function of the islanded the shielding film,
i.e., the function to decrease the internal stress.
[0070] For the above-described reason, in the present invention,
the distance between the adjacent islands is more preferably 2
.mu.m or less.
[0071] The electro-optical device in the second or third aspect of
the present invention may further comprise a mounting case for
mounting the electro-optical device, the mounting case having a
display window formed corresponding to the image display region,
wherein at least one of the second lower shielding film and the
out-of-region shielding film is formed in at least a portion of the
region between the edge of the display window and the edge of the
image display region.
[0072] In this case, the mounting case has the display window
formed so that the image display region can be seen from the
outside of the electro-optical device. Namely, in the display
window portion including the image display region, light is
substantially possibly transmitted, while in the other portions,
light is cut off by the material (for example, preferably a metal
material such as magnesium or an alloy thereof) constituting the
mounting case. This means that the presence of light reflected by
the pattern portion, light passing through the pattern portion, or
light passing through the region other than the region in which the
pattern portion is formed, need not be taken into account as far as
the portion other than the display window is concerned. However, in
the display window except in the image display region, the above
light must be taken into consideration.
[0073] In the present invention, at least one of the second
shielding film and the out-of-region shielding film (simply
referred to as the "shielding film of the present invention"
hereinafter) is formed in at least a portion of the region between
the edge of the display window and the edge of the image display
region, and thus the above-described functions can be exhibited,
and effective shielding can be achieved. At the same time, this
means that the shielding film of the present invention may be
formed in an appropriate necessary area, thereby realizing relative
narrowing of the area. Therefore, the internal stress of the
shielding film can be further decreased, thereby further improving
the reliability of the device.
[0074] In the electro-optical device in the second or third aspect
of the present invention, the lower shielding film, the second
lower shielding film, the in-region shielding film or the
out-of-region shielding film can be provided with the same
characteristics as the lower shielding film of the electro-optical
device in the first aspect of the present invention. Namely, such a
shielding film may be formed on a flat substrate or underlying
insulating film, may comprise a light-absorbing film, particularly
at lest one of a polysilicon film and a high-melting-point metal
film, may comprise a conductive film, or may have a fixed potential
or floating potential. In this case, clearly, the same functions as
described above can be obtained in the electro-optical device in
the second or third aspect of the present invention.
[0075] The electro-optical device in the second or third aspect of
the present invention further comprises a frame shielding film
disposed above the pattern portion in the frame region, the frame
shielding film comprising aluminum.
[0076] In this case, the frame region can be defined by the frame
shielding film disposed above the pattern portion and comprising,
for example, a built-in shielding film formed on the substrate, or
a shielding film formed on the counter substrate opposing the
substrate with an electro-optical material such as a liquid crystal
provided therebetween.
[0077] Particularly, in the present invention, the frame shielding
film comprises at least aluminum, and thus light is easily
reflected to less accumulate heat in the electro-optical device.
Therefore, for example, the stable operation of a thin film
transistor serving as a pixel switching element can be secured,
thereby permitting the stable operation of the electro-optical
device over a relatively long period of time.
[0078] However, with the frame shielding film comprising such a
material having high light reflectivity, it is said that the
occurrence of the light-dark pattern projected around the display
image or the occurrence of a dim light image appearing near the
edge of the image becomes further remarked.
[0079] However, in the present invention, the light-dark pattern
projected outside the display image due to the internally reflected
light, which is reflected by the inner surface of the frame
shielding film, according to the pattern portion can be decreased
by the lower shielding film disposed below the pattern portion.
Furthermore, in the present invention, even when the internally
reflected light reflected by the inner surface of the frame
shielding film passes directly through the substrate, the second
lower shielding film or the out-of-region shielding film can
suppress the occurrence of a dim light image appearing near the
edge of the display image.
[0080] In order to achieve the object of the present invention, an
electronic apparatus comprises each of the above-described
electro-optical devices of the present invention (including the
various forms).
[0081] The electronic apparatus of the present invention comprises
the electro-optical device of the present invention, and thus the
light-dark pattern due to the pattern portion comprising the
wirings and the circuit elements provided in the frame region is
not projected within the display image. It is thus realize various
electronic apparatuses capable of displaying high-quality images,
such as a projection display device, a liquid crystal television, a
cellular phone, an electronic notebook, a word processor, a view
finder-type or monitor direct viewing video tape recorder, a work
station, a picture phone, a POS terminal, a touch panel, etc.
[0082] The operation and advantages of the present invention will
be made appear from the description of embodiments below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0083] FIG. 1 is a plan view showing a TFT array substrate in an
electro-optical device together with components formed on the
substrate according to a first embodiment of the present invention,
as viewed from the counter substrate side.
[0084] FIG. 2 is a sectional view taken along line H-H' in FIG.
1.
[0085] FIG. 3 is a block diagram showing equivalent circuits
comprising various elements provided on a plurality of pixels
arranged in a matrix to form an image display region and wirings,
and peripheral circuits in the electro-optical device of the first
embodiment of the present invention.
[0086] FIG. 4 is an enlarged partial sectional view showing a
portion near the CR portion shown in FIG. 2.
[0087] FIG. 5 is an enlarged partial sectional view showing a
portion of a comparative example, which corresponds to the vicinity
of the CR portion shown in FIG. 2.
[0088] FIG. 6 is a schematic partial perspective view showing a
frame shielding film, data line lead wiring, and a lower shielding
film in the portion shown in FIG. 4.
[0089] FIG. 7 a schematic partial perspective view showing a frame
shielding film and data line lead wiring in the portion of the
comparative example shown in FIG. 5.
[0090] FIG. 8 is a plan view showing a plurality of adjacent pixel
groups on a TFT array substrate on which data lines, scanning
lines, pixel electrodes, etc. are formed in an electro-optical
device according to an embodiment of the present invention.
[0091] FIG. 9 is a sectional view taken along line E-E' in FIG.
8.
[0092] FIG. 10 is an enlarged plan view showing a complementary
transistor constituting a peripheral circuit according to a second
embodiment of the present invention.
[0093] FIG. 11 is a sectional view taken along line A-A' in FIG.
10.
[0094] FIG. 12 is an enlarged plan view showing a complementary
transistor constituting a peripheral circuit according to a third
embodiment of the present invention.
[0095] FIG. 13 is a sectional view taken along line B-B' in FIG.
12.
[0096] FIG. 14 is an enlarged plan view showing a complementary
transistor constituting a peripheral circuit according to a fourth
embodiment of the present invention.
[0097] FIG. 15 is a sectional view taken along line C-C' in FIG.
14.
[0098] FIG. 16 is an enlarged plan view showing a complementary
transistor constituting a peripheral circuit according to a fifth
embodiment of the present invention.
[0099] FIG. 17 is a sectional view taken along line D-D' in FIG.
16.
[0100] FIG. 18 is an enlarged plan view showing a portion in a
sixth embodiment of the present invention, which corresponds to the
vicinity of the portion denoted by character A in FIG. 1.
[0101] FIG. 19 is an enlarged plan view showing a portion in a
conventional example, which corresponds to the vicinity of the
portion denoted by character A in FIG. 1.
[0102] FIG. 20 is an enlarged sectional view showing a portion in
the sixth embodiment of the present invention, which corresponds to
the vicinity of the portion denoted by character CR in FIG. 2.
[0103] FIG. 21 is a schematic sectional view showing a color liquid
crystal projector as an example of a projection color display
device according to an embodiment of the present invention.
REFERENCE NUMERALS
[0104] 1a . . . semiconductor layer, 1a' . . . channel region, 1b .
. . low-concentration source region, 1c . . . low-concentration
drain region, 1d . . . high-concentration source region, 1e . . .
high-concentration drain region, 2 . . . insulating film, 3a . . .
scanning line, 6a . . . data line, 9a . . . pixel electrode, 10 . .
. TFT array substrate, 11a . . . lower shielding film, 12 . . .
underlying insulating film, 16 . . . alignment film, 20 . . .
counter substrate, 21 . . . counter electrode, 22 . . . alignment
film, 30 . . . TFT, 50 . . . liquid crystal layer, 53 . . . frame
shielding film, 70 . . . storage capacitor, 71 . . . relay layer,
81, 83, 85 . . . contact hole, 101 . . . data line driving circuit,
104 . . . scanning line driving circuit, 114 . . . sampling circuit
driving signal line, 115 . . . image signal line, 116 . . . lead
wiring, 202 . . . TFT, 202a-202d . . . complementary TFT, 206 . . .
lead wiring, 300 . . . capacitance line, 301 . . . sampling
circuit, 302 . . . TFT, 501 . . . lower shielding film
DETAILED DESCRIPTION OF EMBODIMENTS
[0105] Embodiments of the present invention will be described below
with reference to the drawings. In each of the embodiments, an
electro-optical device of the present invention is applied to a
liquid crystal device.
First Embodiment
[0106] The whole construction of an electro-optical device
according to a first embodiment of the present invention is first
described with reference to FIGS. 1 and 2. Here, a liquid crystal
device in a built-in driving circuit-type TFT active matrix driving
system is described as an example of electro-optical devices.
[0107] FIG. 1 is a plan view showing a TFT array substrate together
with the components formed thereon, as viewed from the counter
substrate side, and FIG. 2 is a sectional view taken along line
H-H' in FIG. 1.
[0108] In FIGS. 1 and 2, the electro-optical device of this
embodiment comprises a TFT array substrate 10 and a counter
substrate 20 which are disposed opposite to each other. A liquid
crystal layer 50 is sealed between the TFT array substrate 10 and
the counter substrate 20, and the TFT array substrate 10 and the
counter substrate 20 are bonded together with a sealing material 52
provided in a seal region positioned around an image display region
10a.
[0109] In order to bond the TFT array substrate 10 and the counter
substrate 20 together, the sealing material 52 comprises, for
example, an ultraviolet curing resin, a thermal curing resin, or
the like. The sealing material 52 is coated on the TFT array
substrate 10, and then cured by ultraviolet irradiation, heating,
or the like in the manufacturing process. Furthermore, the sealing
material 52 comprises glass fibers or glass beads dispersed
therein, for setting the distance (substrate gap) between the TFT
array substrate 10 and the counter substrate 20 to a predetermined
value. Namely, the electro-optical device of this embodiment is
suitable as a light valve for a small projector for extended
display. However, when the electro-optical device is used as a
large liquid crystal device for 1.times. magnification display,
such as a liquid crystal display or a liquid crystal television,
such a gap material may be contained in the liquid crystal layer
50.
[0110] Furthermore, a light-shielding frame shielding film 53 is
provided in parallel with the inner side of the seal region in
which the sealing material 52 is disposed, so as to define the
image display region 10a. The frame shielding film may be partially
or entirely provided as a built-in shielding film on the TFT array
substrate 10.
[0111] Particularly, in this embodiment, a lower shielding film 501
is partially formed below the frame shielding film 53. The lower
shielding film 501 is partially formed below the frame shielding
film 53 to extend from the outer edge of the image display region
10a to the outer periphery. The structure and the shielding
function of the lower shielding film 501 are described later.
[0112] In the peripheral region of the image display region 10a, a
data line driving circuit 101 and external circuit connection
terminals 102 are provided along one side of the TFT array
substrate 10 in a portion outside the seal region in which the
sealing material 52 is disposed. Furthermore, in the portion
outside the seal region, scanning line driving circuits 104 are
provided along the two sides adjacent to the one side of the TFT
array substrate 10. Also, a plurality of wirings 105 is provided on
the remaining side of the TFT array substrate 10, for connecting
the scanning line driving circuits 104 provided on the two sides of
the image display region 10a. As shown in FIG. 1, vertical
conductive materials 106 having the function as a vertical
conduction terminal between the two substrates are provided at the
four corners of the counter substrate 20. On the other hand, on the
TFT array substrate 10, vertical conduction terminals are provided
at positions corresponding to the four corners of the counter
substrate 20. This can achieve electrical conduction between the
TFT array substrate 10 and the counter substrate 20.
[0113] Particularly, in this embodiment, a sampling circuit 301 for
sampling image signals supplied from the data line driving circuit
101 is provided in the frame region comprising the frame shielding
film 53. Namely, the circuit elements described below, such as TFTs
constituting the sampling circuit 301, are disposed in the frame
region. Furthermore, various wiring portions such as a wiring
portion extending from the data lines provided in the image display
region 10a to the sampling circuit 301, a wiring portion extending
from the data line driving circuit 101 to the sampling circuit 301,
and a wiring portion extending from the scanning lines provided in
the image display region 10a to each of the scanning line driving
circuits 104 are disposed in the frame region.
[0114] In FIG. 2, on the TFT array 10, pixel switching TFTs, and
the wirings such as the scanning lines and the data lines are
formed for pixel electrodes 9a, and an alignment film is further
formed on the pixel electrodes 9a. On the other hand, on the
counter substrate 20, a counter electrode 21 and an alignment film
as an uppermost layer are formed. The liquid crystal layer 50
comprises, for example, a nematic liquid crystal or a mixture of
several types of nematic liquid crystals, and assumes a
predetermined orientation state between two alignment films.
[0115] Besides the data line driving circuit 101, the scanning ling
driving circuits 104, and the sampling circuit 301, a pre-charge
circuit for supplying a pre-charge signal in a predetermined
voltage level to each of the plurality of data lines before image
signals, an inspection circuit for inspecting the quality and
defects of the electro-optical device in the course of manufacture
and at the time of shipment may be formed on the TFT array
substrate 10 shown in FIGS. 1 and 2.
[0116] Next, the circuit configurations and the operation of the
electro-optical device having the above construction will be
described below with reference to FIG. 3. FIG. 3 is a block diagram
showing equivalent circuits comprising various elements of the
plurality of pixels formed in a matrix in the image display region,
and wirings, and the peripheral circuits in the electro-optical
device.
[0117] In the electro-optical device of this embodiment shown in
FIG. 3, the pixel electrode 9a and a TFT 30 for controlling
switching of the corresponding pixel electrode 9a are formed for
each of the plurality of pixels formed in a matrix to form the
image display region, and a data line 6a, to which image signals
are supplied, is electrically connected to the source of the
corresponding TFT 30.
[0118] In the peripheral region outside the image display region
10a, an end (the lower end in FIG. 3) of each of the data lines 6a
is connected to the drain of a corresponding TFT 202 constituting
the sampling circuit 301. On the other hand, image signal lines 115
are respectively connected, through lead wirings 116, to the
sources of the TFTs 202 constituting the sampling circuit 301.
Furthermore, sampling circuit driving signal lines 114 connected to
the data line driving circuit 101 are respectively connected to the
gates of the TFTs 202 constituting the sampling circuit 301.
Therefore, image signals S1, S2, . . . , Sn supplied through the
image signal lines 115 are sampled by the sampling circuit 301
according to the sampling circuit driving signals supplied from the
data line driving circuit 101 through the sampling circuit driving
signal lines 114, and then supplied to the respective data lines
6a.
[0119] The image signals S1, S2, . . . , Sn written in the data
lines 6a may be sequentially supplied in that order, or may be
supplied to each group comprising a plurality of adjacent data
lines 6a.
[0120] The scanning lines 3a are also electrically connected to the
gates of the pixel switching TFTs 30 so that pulsed scanning
signals G1, G2, . . . , Gm are line-sequentially supplied, in that
order, to the scanning lines 3a from the scanning line driving
circuits 104 with predetermined timing. The pixel electrodes 9a are
respectively electrically connected to the drains of the TFTs 30,
and the switches of each of the TFTs 30 serving as the switching
elements are closed for a predetermined time to write the image
signals S1, S2, . . . , Sn supplied from the data lines 6a with
predetermined timing. The image signals S1, S2, . . . , Sn in the
predetermined level written in the liquid crystal as an example of
electro-optical materials through the pixel electrodes 9a are
stored between the TFT array substrate 10 and the counter electrode
21 formed on the counter substrate 20 for a predetermined time. The
orientation and order of the molecules of the liquid crystal vary
with the potential level applied to modulate light, thereby
permitting a gray-scale display. In a normally white mode, the
transmittance of incident light decreases according to the voltage
applied by pixel, while in a normally black mode, the transmittance
of incident light increases according to the voltage applied by
pixel. As a result, light having contrast corresponding to the
image signals is emitted from the electro-optical device as a
whole. In order to prevent a leakage of the image signals stored, a
storage capacitor 70 is added in parallel with a liquid capacitance
formed between each of the pixel electrodes 9a and the counter
electrode 21. Also, capacitance lines 300 fixed at a predetermined
potential and containing fixed potential-side electrodes of the
storage capacitor 70 are provided in parallel with the scanning
lines 3a.
[0121] With respect to the detailed configuration of the frame
region comprising the frame shielding film 53 and the peripheral
region of the electro-optical device shown in FIGS. 1 and 2, the
structure and the function of the lower shielding film 501 provided
in the frame region are mainly described with reference to FIGS. 4
to 7. FIG. 4 is an enlarged partial sectional view showing the
vicinity of the CR portion shown in FIG. 2, and FIG. 5 is an
enlarged partial sectional view showing a portion of a comparative
example, which corresponds to the vicinity of the CR portion shown
in FIG. 2. FIG. 6 is a schematic partial perspective view showing a
portion including the frame shielding film 53, lead wirings 206 of
the data lines 6a, and the lower shielding film 501 shown in FIG.
4, and FIG. 7 a schematic partial perspective view showing a
portion including the frame shielding film 53 and the lead wirings
206 of the data lines in the comparative example.
[0122] As shown in FIG. 4, in this embodiment, various wirings such
as the lead wirings 206 of the data lines 6a, and various circuit
elements such as the TFTs constituting the sampling circuit 301 are
disposed as an example of a pattern portion in the frame region
below the frame shielding film 53. The lower shielding film 501 is
provided below the lead wirings 206 provided in the frame
region.
[0123] In the comparative example shown in FIG. 5, the lower
shielding film 501 is not provided.
[0124] As shown in FIG. 6, in this embodiment, therefore, when
incident light L1 incident from above has high strength and
contains a large quantity of oblique component, as in application
to a projector, the incident light L1 is reflected by the surfaces
of the lead wirings 206 formed by patterning a conductive film of
an Al film, or the incident light passes through the spaces between
the lead wirings 206 according to the reflectance of the lead
wirings 206. The TFT array substrate side (the lower side in FIG.
6) of the lead wirings 206 is covered with the lower shielding film
501. Therefore, of the incident light L1 reflected by the lead
wirings 206 or passing through the spaces between the lead wirings
206 in the vicinity of the periphery of the frame region, i.e., the
vicinity of the periphery of the image display region 10a, the
quantity of light L3 finally mixed with emitted light L.sub.out for
display directly or after internal reflection is significantly
decreased by a quality corresponding to the quantity of light
absorbed or reflected by the lower shielding film 501.
[0125] More specifically, as shown in FIGS. 4 and 6, when light
reflected by the lead wirings 206 travels toward the TFT array
substrate 10 near the frame shielding film 53 because the light is
reflected by the inner surface of the frame shielding film 53, the
quantity of light mixed with the emitted light L.sub.out for
display is decreased by a quantity corresponding to the quantity of
light absorbed or reflected by the lower shielding film 501. With
respect to return light L2 produced when internally reflected
light, which is reflected by the frame shielding film 53, and
light, which is transmitted through the lead wirings 206, are
reflected by the back side of the TFT array substrate 10 and a
polarizing plate, a retardation plate, and dustproof glass, which
are provided on the outside of the TFT arrays substrate, the
quantity of light finally mixed with the emitted light L.sub.out
for display is decreased by a quantity corresponding to the
quantity of light absorbed or reflected by the lower shielding film
501. Furthermore, in a multi-substrate projector, with respect to
internally reflected light produced by further reflection of the
return light L2 by the lead wirings 206 and the frame shielding
film 53, the quantity of light finally mixed with the emitted light
L.sub.out for display is decreased by a quantity corresponding to
the quantity of light absorbed or reflected by the lower shielding
film 501.
[0126] The electro-optical device is contained in a light-shielding
mounting case 800 comprising a resin or the like, and thus leakage
light in the mounting case 800 is absorbed by the inner surface of
the mounting case 800, causing no problem.
[0127] On the other hand, as shown in the comparative example shown
in FIGS. 5 and 7 in which the lower shielding film 501 is not
provided, of the incident light L1 reflected by the lead wirings
206 or passing through the spaces between the lead wirings 206 in
the vicinity of the periphery of the frame region, i.e., the
vicinity of the periphery of the image display region 10a, the
quantity of light L finally mixed with emitted light L.sub.out for
display directly or after internal reflection is significantly
increased, as compared with this embodiment comprising the lower
shielding film 501. In addition, in the comparative example, with
respect to the return light L2 near the frame region, i.e., near
the periphery of the image display region 10a, the quantity of
light reflected by the lead wirings 206 or passing through the
spaces between the lead wirings 206, further reflected by the inner
surface of the frame shielding film, and finally mixed with emitted
light L.sub.out for display directly or after internal reflection
is significantly increased, as compared with this embodiment
comprising the lower shielding film 501.
[0128] Therefore, in this embodiment comprising the lower shielding
film 501 provided below the pattern portion comprising the lead
wirings 206, it is possible to decrease the occurrence of light
having a light-dark pattern due to the light and shade of the
pattern portion and interference of light in the emitted light
L.sub.out for display near the periphery of the image display
region 10a. Therefore, it is effectively possible to prevent the
occurrence of the light-dark pattern due to the pattern portion
near the outside of the display image.
[0129] In this embodiment, the lower shielding film 501 is
preferably formed directly on the flat surface of the TFT array
substrate 10, or on a flat underlying insulating film deposited on
the flat TFT array substrate 10. In this case, substantially no
irregularity occurs in the surface of the lower shielding film 501.
Therefore, even if the incident light L1 and return light L2 shown
in FIGS. 5 and 7 are partially reflected by the lower shielding
film 501, and finally mixed with the emitted light L.sub.out for
display, light reflected by the flat lower shielding film 501 has
substantially no interference, and thus the light-dark pattern due
to interference can be significantly decreased.
[0130] The lower shielding film 501 comprises a single metal, an
alloy, a metal silicide, or a polysilicide, which contains at least
one of high-melting-point metals, for example, Ti (titanium), Cr
(chromium), W (tungsten), Ta (tantalum), Mo (molybdenum), and the
like, or a laminated layer of these materials. The lower shielding
film 501 is preferably formed by using the same film as a lower
shielding film for covering the lower sides of the channel regions
of the pixel switching TFTs 30 in the image display region.
Therefore, the lower shielding film for shielding the pixel
switching TFTs 30 and the lower shielding film 501 for preventing
the occurrence of the light-dark pattern in the frame region can be
simultaneously formed in the same manufacturing process. Thus, it
is possible to simplify the laminated structure on the TFT array
substrate 10 and the manufacturing process.
[0131] In the lower shielding film 501, light shielding may be
mainly performed by reflection, light absorption, or both
reflection and absorption. In the case in which light shielding is
mainly performed by absorption, the incident light L1 and the
return light L2 near the frame region can be attenuated at each
time of incidence on the light-absorbing film constituting the
lower shielding film 501. Particular, when the return light L2 is a
problem, the lower shielding film 501 may be formed in a two-layer
or multi-layer structure comprising a light-absorbing layer formed
on the TFT array substrate 10 side (lower side), and a reflecting
film formed on the opposite side (upper side). On the other hand,
when the incident light L1 is a problem, the lower shielding film
501 may be formed in a two-layer or multi-layer structure
comprising a light-absorbing layer formed on the counter substrate
20 side (upper side), and a reflecting film formed on the opposite
side (lower side). The light-absorbing layer comprises, for
example, at least one of a polysilicon film and a
high-melting-point metal film.
[0132] Furthermore, the lower shielding film 501 is preferably
formed in separated islands having a proper size unit. When the
lower shielding film 501 is formed in the separated islands, the
occurrence of stress due to the lower shielding film 501 can be
relieved, as compared with a case in which the lower shielding film
is formed over the entire frame region.
[0133] In this embodiment, as shown in FIG. 4, the lower shielding
film 501 is formed with an overlap width .DELTA.W in the region
extending from the outer edge of the image display region 10a to
the peripheral side. The overlap width .DELTA.W is can be
previously set according to the incidence angle of the incident
light L1 applied to the frame region. In application to a projector
for extended projection, the incidence angle is generally large,
and thus the overlap width .DELTA.W must be increased for
preventing the occurrence of the light-dark pattern. The
predetermined width can be separately set by experiment, experience
or simulation, or the like in consideration of the specifications
of the actual device.
[0134] A description will now be made of the construction of an
image display region of an electro-optical device according to an
embodiment of the present invention with reference to FIGS. 8 and
9. FIG. 8 is a plan view showing a plurality of adjacent pixel
groups on a TFT array substrate on which data lines, scanning
lines, pixel electrodes, etc. are formed. FIG. 9 is a sectional
view taken along ling E-E' in FIG. 8. In FIG. 9, layers and members
are shown on different contraction scales in order to show the
layers and members each having a recognizable size in this
figure.
[0135] In FIG. 8, on the TFT array substrate of the electro-optical
device, a plurality of transparent pixel electrodes 9a (with the
outer lines shown by dotted lines 9a') is provided in a matrix, and
data lines 6a and scanning lines 3a are provided along the
longitudinal and lateral boundaries between the pixel electrodes
9a.
[0136] Also, the scanning lines 3a are disposed so as to face
channel regions 1a' of a semiconductor layer 1a, the channel
regions 1a' being shown by oblique lines in the figure, and the
scanning lines 3a function as gate electrodes. Furthermore, a pixel
switching TFT 30 in which the corresponding scanning line 3a is
opposed as the gate electrode to the channel region 1a' is provided
at each of the intersections of the scanning lines 3a and the data
lines 6a.
[0137] As shown in FIGS. 8 and 9, a relay layer 71 as a pixel
potential-side capacitance electrode, which is connected to the
high-concentration drain region 1e of each TFT 30 and each of the
pixel electrodes 9a, is disposed opposite to a portion of a
capacitance line 300 as a fixed potential-side capacitance
electrode through a dielectric film 75 to form a storage
capacitance 70.
[0138] In a plan view, the capacitance lines 300 are formed in
stripes extending along the scanning lines 3a, and the portions
overlapping with the TFTs 30 project upward and downward in FIG. 8.
Each of the capacitance lines 300 preferably comprises a multilayer
laminated structure comprising a first film comprising a conductive
polysilicon film having a thickness of about 50 nm, and a second
film comprising a metal silicide film containing a
high-melting-point metal and having a thickness of about 150 nm. In
this structure, the second film functions not only as the fixed
potential-side capacitance electrode of each of the capacitance
lines 300 or the storage capacitors 70, but also as a shielding
layer for shielding the upper side of the corresponding TFT 30 from
incident light.
[0139] Particularly, in this embodiment, the capacitance lines 300
are formed between the scanning lines 3a and the data lines 6a, and
thus capacitances are formed in the regions overlapping with the
scanning lines 3a and the data lines 6a, thereby increasing the
storage capacitors 70.
[0140] On the other hand, a lower shielding film 11a is formed in a
lattice shape below the TFTs 30 on the TFT array substrate 10. The
lower shielding film 11a comprises a single metal, an alloy, a
metal silicide, or a polysilicide comprising at least one of
high-melting-point metals, for example, Ti, Cr, W, Ta, Mo, and the
like, or a laminated film thereof.
[0141] Furthermore, the data lines 6a extending in the longitudinal
direction of FIG. 8 and the capacitance lines 300 extending in the
lateral direction of FIG. 8 are formed to cross each other, and the
lower shielding film 11a is formed in a lattice shape, to define
the aperture regions of the respective pixels.
[0142] As shown in FIGS. 8 and 9, the data lines 6a are
electrically connected, through contact holes 81, to the
high-concentration source regions 1d of the semiconductor layers 1a
each comprising, for example, a polysilicon film. A relay layer
comprising the same film as the relay layer 71 may be formed for
electrically connecting the data lines 6a and the
high-concentration source regions 1d through the relay layer and
two contact holes.
[0143] The capacitance lines 300 are preferably extended from the
image display region 10a (refer to FIG. 1), in which the pixel
electrodes 9a are disposed to the periphery thereof, and
electrically connected, to a constant potential source to have a
fixed potential. As the constant potential source, a constant
potential source for positive power and negative power supplied to
the data line driving circuit 101 and the scanning line driving
circuits 104 may be used, or a constant potential supplied to the
counter electrode 21 of the counter substrate 20 may be used.
Furthermore, like the capacitance lines 300, the lower shielding
film 11a provided below the TFTs 30 may be extended from the image
display region 10a to the periphery thereof, and connected to a
constant potential source for avoiding an adverse effect of a
variation in the potential on the TFTs 30.
[0144] The pixel electrodes 9a are electrically connected to the
high-concentration drain regions 1e of the semiconductor layers 1a
through the relay layers 71 and the contact holes 83 and 85.
[0145] In FIGS. 8 and 9, the electro-optical device comprises the
transparent TFT array substrate 10, and the transparent counter
substrate 20 opposed to the TFT array substrate 10. The TFT array
substrate 10 comprises, for example, a quartz substrate, a glass
substrate, or a silicon substrate, and the counter substrate 20
comprises, for example, a glass substrate or a quartz
substrate.
[0146] As shown in FIG. 9, the pixel electrodes 9a are provided on
the TFT array substrate 10, and an alignment film 16 subjected to a
predetermined orientation treatment such as rubbing or the like is
provided on the pixel electrodes 9a. Each of the pixel electrodes
9a comprises, for example, a transparent conductive film such as an
ITO film or the like. The alignment film 16 comprises, for example,
a transparent organic film such as a polyimide film or the
like.
[0147] On the other hand, on the counter substrate 20, the counter
electrode 21 is formed over the entire surface, and an alignment
film 22 subjected to a predetermined orientation treatment such as
rubbing or the like is provided below the counter electrode 21. The
counter electrode 21 comprises, for example, a transparent
conductive film such as an ITO film or the like. The alignment film
22 comprises a transparent organic film such as a polyimide film or
the like.
[0148] Furthermore, on the counter substrate 20, a shielding film
may be provided in a lattice shape or stripes corresponding to the
non-aperture regions of the respective pixels. In this structure,
the capacitance lines 300 and the data lines 6a, which define the
aperture regions as described above, and the shielding film on the
counter substrate 20 can securely prevent incident light from the
counter substrate 20 side from being incident on the channel
regions 1a', the low-concentration source regions 1b and the
low-concentration drain regions 1c. Furthermore, when the shielding
film on the counter substrate 20 comprises a high-reflection film
formed on at least the incidence side, the shielding film functions
to prevent a temperature rise of the electro-optical device. The
shielding film on the counter substrate 20 is preferably formed
with a small width within the non-aperture region so as not to
narrow the aperture regions of the respective pixels when both
substrates are bonded together. Even with the narrow shielding
film, redundant light can be shielded, and the effect of preventing
a temperature rise in the electro-optical device due to incident
light can be exhibited.
[0149] In the above-described construction, a liquid crystal as an
example of electro-optical materials is sealed in the space
surrounded by the sealing material (refer to FIGS. 1 and 2) between
the TFT array substrate 10 and the counter substrate 20, which are
disposed so that the pixel electrodes 9a face the counter electrode
21, to form a liquid crystal layer 50.
[0150] Furthermore, an underlying insulating film 12 is provided
below the pixel switching TFTs 30. The underlying insulating film
12 has not only the function to insulate the TFTs 30 from the lower
shielding film 11a, but also the function to prevent a change in
the characteristics of the pixel switching TFTs 30 due to
roughening at the time of polishing of the surface of the TFT array
substrate 10, or strains remaining after cleaning, because the
underlying insulating film 12 is formed over the entire surface of
the TFT array substrate 10.
[0151] In FIG. 9, each of the pixel switching TFTs 30 has a LDD
(Lightly Doped Drain) structure comprising the corresponding
scanning line 3a, the channel region 1a' of the semiconductor layer
1a in which the channel is formed by an electric field from the
scanning line 3a, the insulating film 2 comprising a gate
insulating film for insulating the scanning line 3a from the
semiconductor layer 1a, the low-concentration source region 1b and
the low-concentration drain region 1c of the semiconductor layer
1a, and the high-concentration source region 1d and the
high-concentration drain region 1e of the semiconductor layer
1a.
[0152] Furthermore, a first interlayer insulating film 41 is formed
on the scanning lines 3a, the contact holes 81 reaching the
high-concentration source regions 1d, and the contact holes 83
reaching the high-concentration drain regions 1e being formed in
the first interlayer insulating film 41.
[0153] The relay layers 71 and the capacitance lines 300 are formed
on the first interlayer insulating film 41, and a second interlayer
insulating film 42 is formed thereon, the contact holes 81 reaching
the high-concentration source regions 1d, and the contact holes 85
reaching the relay layers 71 being formed in the second interlayer
insulating film 42.
[0154] The data lines 6a are formed on the second interlayer
insulating film 42, and a planarized third interlayer insulating
film 43 is formed on the data lines 6a, the contact holes 85
reaching the relay layers 71 being formed in the third interlayer
insulating film 43. The pixel electrodes 9a are provided on the
upper surface of the third interlayer insulating film 43.
[0155] In this embodiment, the surface of the third interlayer
insulating film 43 is planarized by CMP (Chemical Mechanical
Polishing) processing or the like to decrease orientation defects
in the liquid crystal in the liquid crystal layer 50 due to the
steps caused by the wirings and the elements provided below the
third interlayer insulating film 43.
[0156] As described above, in the first embodiment, the lower
shielding film 501 is provided to decrease the light-dark pattern
projected near the outside of the display image due to the pattern
portion comprising the wirings such as the lead wirings of the data
lines, and the circuit elements such as the TFTs 202, which are
provided in the frame region. Therefore, the frame shielding film
53 need not be wide for concealing the light-dark pattern, thereby
permitting the formation of the large image display region 10a.
[0157] In addition, in the first embodiment, the lower shielding
film 501 is provided in a portion corresponding to the pattern
portion comprising the wirings such as the lead wirings of the data
lines, and the circuit elements such as the TFTs 202, which are
provided in the frame region, not formed over the entire frame
region. Therefore, the occurrence of stress can be decreased, as
compared with a case in which the lower shielding film is formed
over the entire frame region.
[0158] In the above-described embodiment, as shown in FIG. 9, the
surface of the third interlayer insulating film 43 is planarized to
decrease the steps which are produced in the regions of the surface
(the surface of the third interlayer insulating film 43) below the
pixel electrodes 9a along the data lines 6a and the scanning lines
3a by lamination of many conductive layers. However, instead of or
in addition to this, grooves may be formed in the TFT array
substrate 10, the underlying insulating film 12, the first
interlayer insulating film 41, the second interlayer insulating
film 42 or the third interlayer insulating film 43 so that the
wirings such as the data lines 6a and the like, and the TFTs 30 are
buried in the grooves to planarize the surface. Alternatively, the
upper surface of the second interlayer insulating film 42 may be
planarized by CMP processing or using an organic or inorganic SOG
to planarize the surface.
[0159] Next, second to fourth embodiments relating to examples of
the planar shape of the lower shielding film 501 having the above
structure, and modified embodiments thereof will be described
below. In each of these embodiments, the lower shielding film 501
comprises a light shielding conductive film. Therefore, each of the
embodiments relates to an example of the shape of the lower
shielding film 501 suitable for decreasing the adverse effect of
variations in the electrical state or potential of the lower
shielding film 501 disposed in the frame region on the operation of
the circuit elements such as the TFTs 202 disposed in the same
frame region.
Second Embodiment
[0160] An electro-optical device according to a second embodiment
of the present invention will be described with reference to FIGS.
10 and 11. FIG. 10 is an enlarged plan view of a complementary TFT
as an example of a circuit element formed in the frame region in
the second embodiment, and FIG. 11 is a sectional view taken along
line A-A' in FIG. 10. In FIGS. 10 and 11, the same components as
the first embodiment shown in FIGS. 1 to 9 are denoted by the same
reference numerals, and a description thereof is omitted.
[0161] As shown in FIGS. 10 and 11, a complementary TFT 202a
comprises a semiconductor layer 320 comprising a P-channel region
320p and a N-channel region 320n. Also, the complementary TFT 202a
comprises a combination of a P-channel TFT 202p and a N-channel TFT
202n comprising an end of wiring 316 as a gate electrode (input
side), ends of low-potential wiring 321 and high-potential wiring
322 as source electrodes, and an end of wirings 306 as a drain
electrode (output side). Like the pixel switching TFTs 30, each of
the P-channel TFT 202p and the N-channel TFT 202n may have a LDD
structure. Particularly, in the second embodiment, a lower
shielding film 501a comprising a conductive film such as a
high-melting-point metal film is formed in separated islands, and
each island portion covering at least the lower side of the
complementary TFT 202a has a floating potential. The other
components are the same as the first embodiment described above
with reference to FIGS. 1 to 9.
[0162] Therefore, in the second embodiment, the lower shielding
film 501a has a floating potential, and thus the adverse effect of
a variation in the potential of the lower shielding film 501 on the
characteristics of the complementary TFT 202a can be effectively
prevented.
[0163] In the second embodiment, like the lower shielding film 11a
provided in the image display region 10a, the lower shielding film
501a except the islands portions facing the complementary TFTs 202a
may be formed in such a manner that a fixed potential is supplied
thereto.
Third Embodiment
[0164] An electro-optical device according to a third embodiment of
the present invention will be described with reference to FIGS. 12
and 13. FIG. 12 is an enlarged plan view of a complementary TFT as
an example of a circuit element formed in the frame region in the
third embodiment, and FIG. 13 is a sectional view taken along line
B-B' in FIG. 12. In FIGS. 12 and 13, the same components as the
first embodiment shown in FIGS. 1 to 9 and the second embodiment
shown in FIGS. 10 and 11 are denoted by the same reference
numerals, and a description thereof is omitted.
[0165] As shown in FIGS. 12 and 13, in the third embodiment, unlike
in the second embodiment, particularly a lower shielding film 501b
comprising a conductive film such as a high-melting-point metal
film is not formed in separated islands, but two slits are formed
along two gate electrodes of each complementary TFT 202b. The other
components are the same as the second embodiment described above
with reference to FIGS. 10 and 11.
[0166] Therefore, in the third embodiment, it is possible to
decrease capacitance coupling between the source and drain
electrodes of each complementary TFT 202b due to the parasitic
capacitance between the lower shielding film 501b and the source
electrode, and the parasitic capacitance between the lower
shielding film 501b and the drain electrode, thereby effectively
preventing the adverse effect of a variation in the potential of
the lower shielding film 501b on the characteristics of the
complementary TFTs 202b.
[0167] The lower shielding film 501b may have the slits each having
a width of, for example, about 1 .mu.m. Even when such slits are
formed, the slits cause only a relatively small light-dark pattern
because the gate electrodes comprising a conductive polysilicon
film exhibit some light absorbability.
[0168] In the third embodiment, like the lower shielding film 11a
provided in the image display region 10a, the lower shielding film
502b may be formed in such a manner that a fixed potential is
supplied thereto through an extended portion 502.
Fourth Embodiment
[0169] An electro-optical device according to a fourth embodiment
of the present invention will be described with reference to FIGS.
14 and 15. FIG. 14 is an enlarged plan view of a complementary TFT
as an example of a circuit element formed in the frame region in
the fourth embodiment, and FIG. 15 is a sectional view taken along
line C-C' in FIG. 14. In FIGS. 14 and 15, the same components as
the first embodiment shown in FIGS. 1 to 9 and the second
embodiment shown in FIGS. 10 and 11 are denoted by the same
reference numerals, and a description thereof is omitted.
[0170] As shown in FIGS. 14 and 15, in the fourth embodiment,
unlike in the first embodiment, particularly a lower shielding film
501c comprising a conductive film such as a high-melting-point
metal film is not formed in separated large islands based on the
semiconductor layers 320 of complementary TFTs, but formed in
separated small islands based on the source and drain regions of
the semiconductor layer 320 of each complementary TFT 202c. The
other components are the same as the second embodiment described
above with reference to FIGS. 10 and 11.
[0171] Therefore, in the fourth embodiment, it is possible to
decrease capacitance coupling between the source and drain
electrodes of each complementary TFT 202c due to the parasitic
capacitance between the lower shielding film 501c and the source
electrode, and the parasitic capacitance between the lower
shielding film 501c and the drain electrode, thereby effectively
preventing the adverse effect of a variation in the potential of
the lower shielding film 501c on the characteristics of the
complementary TFTs 202c.
[0172] The spaces between the small islands of the lower shielding
film 501c may be, for example, about 1 .mu.m. Even when such spaces
are formed, the spaces cause only a relatively small light-dark
pattern because the gate electrode comprising a conductive
polysilicon film exhibits some extent of light absorbability.
[0173] In the fourth embodiment, like the lower shielding film 11a
provided in the image display region 10a, the lower shielding film
502c except the island portions facing the complementary TFTs 202c
may be formed in such a manner that a fixed potential is supplied
thereto.
Fifth Embodiment
[0174] An electro-optical device according to a fifth embodiment of
the present invention will be described with reference to FIGS. 16
and 17. FIG. 16 is an enlarged plan view of a complementary TFT as
an example of a circuit element formed in the frame region in the
fifth embodiment, and FIG. 17 is a sectional view taken along line
D-D' in FIG. 16. In FIGS. 16 and 17, the same components as the
first embodiment shown in FIGS. 1 to 9 and the second embodiment
shown in FIGS. 10 and 11 are denoted by the same reference
numerals, and a description thereof is omitted.
[0175] As shown in FIGS. 16 and 17, in the fifth embodiment,
particularly a lower shielding film 501d comprising a conductive
film such as a high-melting-point metal film is formed in separated
large islands based on the semiconductor layers 320 of
complementary TFTs, but unlike in the second embodiment, the island
portions do not have a floating potential. Each of the island
portions is connected to the gate electrode (the input side) at an
end of wiring 316 through a contact hole 503 to have the same
potential as the gate electrode. The other components are the same
as the second embodiment described above with reference to FIGS. 10
and 11.
[0176] Therefore, in the fifth embodiment, back channels can be
formed by the island portions of the lower shielding film 501d,
thereby improving the transistor characteristics of the
complementary TFTs 202d.
[0177] In the fifth embodiment, like the lower shielding film 11a
provided in the image display region 10a, the lower shielding film
502d except the island portions facing the complementary TFTs 202d
may be formed in such a manner that a fixed potential is supplied
thereto.
[0178] In each of the above-described embodiments described above
with reference to FIGS. 1 to 17, the data line driving circuit 101
and the scanning line driving circuit 104 may be electrically and
mechanically connected to a driving LSI, which is mounted on, for
example, a TAB (Tape Automated Bonding) substrate, through an
anisotropic conductive film provided in the periphery of the TFT
array substrate 10 instead of being provided on the TFT array
substrate 10. Furthermore, a polarizing film, a retardation film, a
polarizing plate, and the like are provided in any desired
direction on each of the incidence side of the counter substrate 20
and the emission side of the TFT array substrate 10 according to
the operation mode, for example, a TN (Twisted Nematic) mode, a VA
(Vertically Aligned) mode, a PDLC (Polymer Dispersed Liquid
Crystal) mode, or the like, and a normally white mode/normally
black mode.
Sixth Embodiment
[0179] An electro-optical device according to a sixth embodiment of
the present invention will be described with reference to FIGS. 18
to 20. FIG. 18 is an enlarged plan view of a portion in the sixth
embodiment, which corresponds to the portion A shown in FIG. 1, and
FIG. 19 is an enlarged plan view of a portion in a comparative
example, which corresponds to the portion A shown in FIG. 1. FIG.
20 is an enlarged sectional view of a portion in the sixth
embodiment, which corresponds to the portion CR shown in FIG. 2. In
FIGS. 18 to 20, the same components as the first embodiment shown
in FIGS. 1 to 9 and the second embodiment shown in FIGS. 10 and 11
are denoted by the same reference numerals, and a description
thereof is omitted.
[0180] In FIG. 18, as described above in the first embodiment, the
lead wirings 206 of the data lines 6a are formed on the TFT array
substrate 10, and TFTs 202a constituting the sample circuit 301
described above with reference to FIG. 3 are respectively connected
to ends of the lead wirings 206. Furthermore, in FIG. 18, lead
wirings 208 (corresponding to an example of the "pattern portion"
of the present invention) of the scanning lines 3a are formed. A
scanning line driving circuit (refer to FIG. 1) is connected to the
extended end (not shown in the drawing) of the lead wirings 208.
Also, in FIG. 18, various wirings 210 and 212 are formed for
supplying a predetermined potential to the counter electrode on the
counter substrate 20 (refer to the vertical conductive materials
106 shown in FIG. 1). Furthermore, like in the above embodiments,
the lower shielding films 501 and 501a are formed for decreasing
the number of the lead wirings 206a or the TFTs 202a and for
partially covering the TFT array substrate 10 sides thereof (refer
to FIGS. 4 to 6 or FIGS. 10 and 11). The wirings 210 and 121
correspond to an example of a "second pattern portion" in the sixth
embodiment.
[0181] Particularly, in the sixth embodiment, besides the lower
shielding films 501 and 501a, a lower shielding film 11a (refer to
FIG. 9) is formed to cover the TFT array substrate 10 sides of the
TFTs 30 serving as the pixel switching elements formed in the image
display region 10a, and an out-of-region shielding film 501A is
formed to cover the entire peripheral region around the image
display region 10a. All the three types of the shielding films are
simultaneously formed as the same film in a manufacturing step.
[0182] Of these shielding films, the structure of the out-of-region
shielding film 501A is described in detail below with reference to
FIG. 18.
[0183] The lower shielding film 501 is formed to cover the lead
wirings 206, as shown in the upper left portion of FIG. 18 (refer
to FIG. 4 or 6). The lower shielding film 501a is formed to cover
the TFTs 202a constituting the sample circuit 301 as shown in a
middle portion of FIG. 18 (refer to FIG. 10 or 11). In addition, in
FIG. 18, a lower shielding film 501z is provided to cover the lead
wirings 208 led from the scanning lines 3a. These shielding films
have the same purpose and exhibit the same function as the lower
shielding film in the above embodiments.
[0184] The out-of-region shielding film 501A of the sixth
embodiment comprises a second lower shielding film 501Aa formed in
the region R1 other than the region in which the lower shielding
films 501a and 501a are formed, integrally with the lower shielding
films 501a and 501a. Namely, the second lower shielding film 501Aa
is formed in the region R1 other than the region in which the lead
wirings 206 or the TFTs 202a are formed, in the frame region (shown
by thick lines in FIG. 18). Furthermore, the out-of-region
shielding film 501A comprises a true out-of-region shielding film
501Ab formed between the wirings 210 and 212 provided in the region
R of the frame region. The true out-of-region shielding film 501Ab
may be not formed below the wirings 210 and 212. Namely, the true
out-of-region shielding film 501Ab is divided.
[0185] In brief, in the sixth embodiment, the out-of-region
shielding film 501A is formed to cover almost the entire region of
the TFT array substrate 10 except in some cases in which the
out-of-region shielding film 501A is not formed in the region in
which the wirings or the circuit elements are formed, as the
wirings 210 or 212.
[0186] As shown in FIG. 18, slits are formed at appropriate
positions of the out-of-region shielding film 501A. Namely, the
out-of-region shielding film 501A is divided into islands. In the
sixth embodiment, the distance between the islands of the
out-of-region shielding film 501A is set to 2 .mu.m or less. The
out-of-region shielding film 501A having such a shape can be easily
formed by proper patterning.
[0187] The out-of-region shielding film 501A has the following
function: In the comparative example shown in FIG. 19 in which the
out-of-region shielding film 501A of the sixth embodiment is not
formed, the portion of the TFT array substrate 10, which
corresponds to the out-of-region shielding film 501A, is exposed
(of course, the various interlayer insulating films 12, 41, 42 and
43 are formed). Therefore, incident light possibly passes
"directly" through that portion, and is possibly mixed with light
L.sub.out (refer to FIG. 4 or 6) for forming a display image to
affect the image display. For example, when the above-described
return light passes through the region R1, is reflected by the
frame shielding film 53, and again passes through the region R1,
the light is highly likely to be mixed with the light L.sub.out for
forming the display image, thereby possibly causing a dim light
image near the edge of the image.
[0188] However, in the sixth embodiment, as described above, the
out-of-region shielding film 501A comprising the second lower
shielding film 501Aa and the true out-of-region shielding film
501Ab is formed in the regions R1 and R2, thereby preventing the
above phenomenon. Therefore, in the sixth embodiment, it is
possible to prevent the occurrence of a dim light image near the
edge of the display image, and display a higher-quality image with
a good appearance.
[0189] In the sixth embodiment, the out-of-region shielding film
501A is divided as described above, or the true out-of-region
shielding film 501Ab formed between the wirings 210 and 212 is
divided into large parts according to place. Therefore, the
internal stress can be relatively decreased, as compared with a
case in which such a shielding film is formed over the entire
region. It is thus possible to prevent the phenomenon that the
out-of-region shielding film 501A is broken by its own internal
stress, or cracks occur in the peripheral components (for example,
the underlying insulating film 12, and the like), thereby providing
an electro-optical device with high reliability.
[0190] When the out-of-region shielding film 501A is divided into
islands in the region R1, the distance between the islands is 2
.mu.m or less. Therefore, light passing though the spaces between
the islands is unlikely to again pass through the spaces after
being reflected by the frame shielding film 53 at the back of the
out-of-region shielding film 501A. Consequently, the light is
highly unlikely to be mixed with the light L.sub.out for forming
the display image, thereby significantly decreasing the influence
of the spaces on the display image. Therefore, in the sixth
embodiment, it is possible to obtain the initial effect of the
out-of-region shielding film 501A, i.e., the function to prevent
the occurrence of a light image around the display image, while
obtaining the function of the island-formed shielding film 501A,
i.e., the function to decrease internal stress.
[0191] Although, in the sixth embodiment, the out-of-region
shielding film 501A is formed to cover almost the entire surface of
the TFT array substrate, the out-of-region shielding film 501A is
not necessarily formed over the entire surface of the TFT array
substrate 10 from the viewpoint of the present invention. In fact,
in FIGS. 18 and 19, the out-of-region shielding film 501A is
divided at an appropriate position, and it is thus apparent that
the out-of-region shielding film 501A is not necessarily formed
over the entire region of the TFT array substrate 10.
[0192] More specifically, for example, the out-of-region shielding
film of the present invention may be formed only in the portion WW
shown in FIG. 20. In FIG. 20, the portion WW is positioned between
the edge 801a of the display window formed in the mounting case and
the edge of the lower shielding film 501. This is because traveling
of light is cut off by the mounting case 801 in the portions other
than the portion WW, and it is thus thought that the "direct"
passage of light substantially occurs only in the portion WW. It is
thus sufficient that the out-of-region shielding film is formed
only in the portion WW (refer to reference numeral 501B or
traveling of light LA).
[0193] In this embodiment, light shielding can be effectively
realized, and the occurrence of the problem due to the internal
stress of the out-of-region shielding film 501B shown in FIG. 20
can be suppressed because the out-of-region shielding film 501B is
formed in an appropriate necessary area.
[0194] Since the electro-optical device of each of the embodiments
is applied to a projector, three electro-optical devices are
respectively used as RGB light values, and color lights, which are
produced by separation through RGB color separation dichroic
mirrors, are respectively incident as incident lights on the light
valves. In each of the embodiments, a color filter is not provided
on the counter substrate 20. However, in the counter substrate 20,
a RGB color filter may be formed in predetermined regions facing
the pixel electrodes 9a together with a protective film. In this
case, besides the projector, the electro-optical device of each of
the embodiments can be applied to a direct viewing or reflective
color electro-optical device. Alternatively, a microlens may be
formed on the counter substrate 20 corresponding to each of the
pixels. A color filter layer may be formed, by using color resist,
below the pixel electrodes 9a facing the RGB colors formed on the
TFT array substrate 10. In this case, the efficiency of convergence
of incident light can be improved to realize a bright
electro-optical device. Furthermore, interference layers having
different refractive indexes may be deposited on the counter
substrate 20 to form a dichroic filter for making the RGB colors by
using interference of light. By using the counter substrate with
the dichroic filter, a brighter color electro-optical device can be
realized.
(Electronic Apparatus According to Embodiment)
[0195] The whole construction, particularly the optical
construction, of a projection color display device will be
described as an example of an electronic apparatus using one of the
above-described electro-optical devices as a light valve according
to an embodiment of the present invention. FIG. 21 is a schematic
sectional view of a projection color display device.
[0196] In FIG. 21, a liquid crystal projector 1100 as an example of
the projection color display device of this embodiment comprises
three liquid crystal modules each comprising a liquid crystal
device in which driving circuits are mounted on a TFT array
substrate, the modules being respectively used as RGB light valves
100R, 100G and 100B. In the liquid crystal projector 1100, when
incident light is emitted from a lamp unit 1102 of a white light
source such as a metal halide lamp or the like, the incident light
is separated into light components R, G and B corresponding to the
three primary colors RGB by three mirrors 1106 and two dichroic
mirrors 1108, and these light components are respectively
introduced into the light valves 100R, 100G and 100B corresponding
to the respective colors. Particularly, B light is introduced
through a relay lens system 1121 comprising an incidence lens 1122,
a relay lens 1123 and an emission lens 1124 in order to prevent a
light loss due to a long optical path. Then, the light components
corresponding to the primary colors are modulated by the light
valves 100R, 100G and 100B, again combined by a dichroic prism
1112, and projected as a color image on a screen 1120 through a
projector lens 1114.
[0197] The electro-optical device of the present invention can also
be applied to an electrophoretic device, an EL device, etc.
[0198] The present invention is not limited to the above
embodiments, and appropriate modification can be made within the
scope of the gist and idea of the present invention, which can be
found from the claims and the specification. The technical field of
the present invention also include an electro-optical device and an
electronic apparatus according to modified embodiments.
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